/*
 * Unidata Platform Community Edition
 * Copyright (c) 2013-2020, UNIDATA LLC, All rights reserved.
 * This file is part of the Unidata Platform Community Edition software.
 * 
 * Unidata Platform Community Edition is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * Unidata Platform Community Edition is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <https://www.gnu.org/licenses/>.
 */

package org.unidata.mdm.core.type.monitoring.collector;

import java.util.Collections;
import java.util.List;
import java.util.Queue;

import io.prometheus.client.Collector;
import io.prometheus.client.GaugeMetricFamily;

public class QueueSizeCollector extends Collector {

    private final Queue<?> queue;

    private final String metricName;
    private final String metricHelpText;

    public static void createAndRegister(final Queue<?> queue, final String metricName, final String metricHelpText) {
        new QueueSizeCollector(queue, metricName, metricHelpText).register();
    }

    public QueueSizeCollector(final Queue<?> queue, final String metricName, final String metricHelpText) {
        this.queue = queue;
        this.metricName = metricName;
        this.metricHelpText = metricHelpText;
    }

    @Override
    public List<MetricFamilySamples> collect() {
        return Collections.singletonList(new GaugeMetricFamily(metricName, metricHelpText, queue.size()));
    }
}
